There is known a fixing device provided in an image-forming apparatus such as a printer and a copying machine for thermally fixing a toner image to a sheet by heating the sheet. Such a fixing device employs a belt and a guide member in contact with an inner peripheral surface of the belt for guiding movement of the belt.
Japanese Patent Application Publication No. H05-027625 discloses such type of fixing device that is provided with a guide member having protrusions protruding from an outer surface of the guide member toward the surface of the belt for reducing sliding resistance between the belt and the guide member.